Apparatus for making spark chamber wire arrays

ABSTRACT

An apparatus for producing curved or flat wire arrays for use in wire spark chamber devices having a wire spool holding means and wire feeding device; tensioning means; wire winding and spacing device; and a device for stretching and shaping the array. The wire is fed over tensioning pulleys about a threaded rod onto a wire winding and spacing device which comprises a support cylinder. The wound wires are attached to lucite strips mounted on the cylinder and then cut and removed to form a loose wire array. The wire array is then clamped in the stretching and shaping device which stretches the wires and forms the surface to the desired curvature.

United States Patent [1 1 Whetstone et al.

[ 1 APPARATUS FOR MAKING SPARK CHAMBER WIRE ARRAYS [73] Assignee: Science Accessories Southport, Conn.

[22] Filed: Dec. 14, 1970 [21] Appl. No.1 97,581

Corporation,

[52] U.S. Cl. ..29/25.2, 29/2519, 140/71.5 [51] Int. Cl ..H 01j 9/06, H01j9/48 [58] Field ofSearch ..29/25.l,25.11,25.13,25.19,

[56] References Cited UNITED STATES PATENTS 1,999,806 4/1935 Eitel et a1. ..140/71.5 X 2,610,387 9/1962 Borland et all. 140/7 1 .5 X 2,824,251 2/1958 Patterson .140/71 5 3,130,757 4/1964 Schellack .140/71 5 3,244,200 4/1966 Stccker v ..140/7l.5

[ 1 Feb. 6, 1973 3,600,778 8/1971 Martin ..140/71.5 X

FOREIGN PATENTS OR APPLICATIONS 1,092,756 4/1955 France ..140/7l.5

Primary Examiner-J. Spencer Overholser Assistant ExaminerRichard Bernard Lazarus Att0rneyFrank R. Trifari [57] ABSTRACT An apparatus for producing curved or flat wire arrays for use in wire spark chamber devices having a wire spool holding means and wire feeding device; tensioning means; wire winding and spacing device; and a device for stretching and shaping the array. The wire is fed over tensioning pulleys about a threaded rod onto a wire winding and spacing device which comprises a support cylinder. The wound wires are attached to lucite strips mounted on the cylinder and then cut and removed to form a loose wire array. The wire array is then clamped in the stretching and shaping device which stretches the wires and forms the surface to the desired curvature.

1 Claim, 5 Drawing Figures PAIENTEIJFEB 6 I978 sum Inf 2 3.714.689

'3 as 31 23 22 I I9 20 w w,

' w I l -23 n a as '5 v 24 as f AGE" INVENTORS. ALBERT WHETSTONE STANLEY c. PHILLIPS SAMUEL FINE SHEET 20F 2 PAIENTEDFEB Sim Fig. 4

AG NT APPARATUS FOR MAKING SPARK CHAMBER WIRE ARRAYS BACKGROUND OF THE INVENTION This invention relates generally to the field of experimentation in high energy physics and more specifically to the spark chamber device used as an experimental tool in this field. The present invention is specifically directed to a method and apparatus for manufacturing the spark chamber and the general object of the present invention is to provide a means for easily and rapidly producing a spark chamber which can have any desired surface configuration, such as any form of curved surface or flat surface.

The use of the wire spark chamber device as an experimental technique in high energy physics has been steadily increasing over the past few years and is emerging as a dominant instrument in this field. The wire spark chamber has become a popular tool as the result of the on-line computer which is used for immediate analysis of the data acquired from the spark chamber device. The wire spark chamber, when used with any of the commonly acceptable read-out systems, such as the ferrite core read-out or the magnetostrictive read-out system, is exceptionally efficient in locating and tracking trajectories of high energy particles. It is a relatively inexpensive and easy to use experimental tool and it is therefore expected that wire spark chambers will become an evermore prominent expedient for the physicist in years to come.

The wire spark chamber construction usually comprises a pair of spaced-parallel wire screen meshes or wire woven cloth, each stretched and supported in a frame. The wire mesh usually consists of nylon monafilament strands extending in one direction and copper or aluminum wire, woven between the nylon strips extending in a direction perpendicular to the nylon strands. Glass fiber is frequently used instead of the nylon monafilament. The conductive wires of one of the woven wire mesh screens of the spark chamber are oriented in the Y direction and the wires of the other mesh are oriented in the X direction. The two wire screens are spaced apart in flat parallel relationship and a noble gas is maintained between them. High voltage pulses are applied across the screens so that when an ionized particle passes therethrough a spark discharge occurs from one screen to the other. The X and Y coordinates, at which the spark took place, can be determined from the read-out system connected to both the X wire screen and the Y wire screen. A series of wire spark chambers may be placed along the Z direction extending from a source of high-energy particles, so that as the particle passes through the line of chambers, its trajectory can be determined and the X, Y, Z coordinates may be tracked.

An array of wire spark chambers for determining the trajectory of an ionized particle utilizing wire screens, such as have been known and used in the art, as described above, have limited capabilities because of the traditional flat configuration of the spark chamber screens. A source of high energy particles frequently propogates ionized particles in various directions and it has become desirable to track those particles in the various directions. The use of curved spark chambers would greatly facilitate this and would add to the versatility of the spark chamber device. Attempts have been made to form curved surface wire spark chambers, however, such attempts have been unsuccessful in the past principally because the typical woven mesh wire screen cannot be curved to the desired shape due to the interwoven nylon or fiber materials used for support. If an attempt is made to curve the wire screens, the wire strands tend to buckle or peak at points of intersection with the nylon fibers.

It is accordingly one object of the present invention to provide a method and means for producing wire spark chamber devices which can be formed of wire screens having curvilinear surfaces which can be used in an evermore versatile manner in experimental physics.

The read-out systems for use with the present invention would be comparable to read-out systems presently used with flat wire arrays.

Another object of the present invention is to provide apparatus for manufacturing wire array which is not of the woven type and therefore avoids the disadvantages of interwoven nylon fibers, therefore being particularly well suited for use in curved spark chamber devices.

A further object of the present invention is to provide a method of manufacturing a spark chamber device which is rapid, efficient and inexpensive.

SUMMARY OF THE INVENTION In order to accomplish the foregoing objectives, the present invention provides an apparatus comprised principally of three main sections, to wit: a wire spool holding, feeding and tensioning device; a wire winding and spacing device; and a wire array stretching and shaping device. The wire spool holding, feeding and tensioning device includes means for rotatably supporting a wire spool so that the wire may be fed to the winding and spacing device, a friction braking mechanism, a set of pulleys for feeding and directing the wire and a set of spring-loaded arms and floating rollers to absorb jerks and shocks so as to maintain the wire in adequate uniform tension as the wire is unwound. The wire winding and spacing device comprises a smooth surfaced cylinder for receiving the wire to be fed and wound thereabout uniformly across its surface, and a threaded rod spaced from the cylinder having its longitudinal axis parallel to the axis of the cylinder, and a combination of pulleys so that when the cylinder is rotated the wire will pass over the threaded rod and onto the cylinder with an appropriate pitch determined by the pitch of the rod. The shaping and stretching device generally comprises a pair of clamps which may have any desired curved configuration such as eliptical, parabolic, circular, etc.. The wire array, after being cut and removed from the receiving cylinder, is placed in the clamps and stretched to the desired shape.

Other objects, advantages and features of the present invention will become more apparent from the following detailed description in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a side elevational schematic view as seen along lines I-I of FIG. 2 showing the wire feeding and tensioning device and the wire winding and spacing device,

FIG. 2 is a plan view showing the wire feeding and tensioning device and the wire winding and spacing device of the present inverition,

FIG. 3 is a plan view of the wire array after it has been cut and removed from the wire winding and spacing device,

FIG. 4 is a side elevational view of the stretching and shaping device for forming a wire array into a particular curved shape, and

FIG. 5 is a plan view of the stretching and shaping device shown in FIG. 4.

DESCRIPTION OF THE INVENTION Referring now to the particular embodiment of the present invention as illustrated in the accompanying drawings there is shown in FIGS. I and 2 that portion of the invention referred to as the wire spool holding,

. wire-feeding and tensioning device and the'wire-winding and spacing device. Various elements of. these devices are supported in a single unit defined between a pair of side frames and 1 1. A threaded rod 13 is supported on shafts 14 and 15 betweenthe side frames 10 and 11 in a non-rotatable manner and is intended as the wire-spool holding device so that a spool of wire 16 may be carried on the threaded rod '13. The wire spool 16 is provided with internal threads for meshing with the threaded rod 13 so that as the wire W is unwound from the spool 16 causing rotation thereof about the rod 13, the spool will be caused to axially advance along the rod 13; As will be understood from the operation of the device, to be described more fully hereinafter, the wire being unwound from the spool 16 is intended to be wound about the cylinder 31 in a spaced apart manner to ultimately form the grid arrangement shown in FIG. 3 Axial movement of the spool 16 along threaded spool holding rod 13 is therefore desirable so that as the wire W is wound on the cylinder 31, being spaced therealong by wire guide screw 23, undesirable tension or kinks in the wire will be avoided by avoiding an angular feed to the cylinder. The wire is rather fed in a straight line direction from the point of unwinding from the spool 16 to the point of winding about the cylinder 31.

The wire tensioning mechanism comprises a floating roller 17 biased in a direction so as to tension the wire W as it passes thereover. One such means for biasing the floating roller 17 is the use of a spring 18 for supporting the roller 17 from a pivotally mounted arm 21. The arm 21 is mounted for pivotal movement about a pivot point 22 so that the floating roller 17 will be in a straight line relationship with the spool 16 and the point of winding onto cylinder 31. Only one such floating roller is shown for the convenience of description, however it is to be understood that in practice a series of rollers and spring-loaded arms may be desirable for maintaining proper tension. The tensioning mechanism further includes a friction braking device 20, schematically shown in FIG. 1 as a pair of brake shoes, for acting on a brake collar 19 secured to one end of the spool 16. Sufficient braking force is applied to the collar so as to maintain proper tension in the wire in combination with the floating roller and spring device.

A wire guide screw 23, for feeding the wire to the cylinder 31 is rotatably journalled between side frames 10 and 11 on shafts 24 and 25. The wire W is directed from the spool 16 over the tension pulley 17 and around wire guide screw 23-onto the cylinder 31, so that as the screw 23 is rotated the wire W will be advanced about and along the cylinder 31. Wire spool holding rod 13 and wire guide screw 23 have the same pitch so that the wire spool 16 is advanced along the rod 13 at the same speed that the wire W is advanced along rod 23.

The wire winding and spacing device consists of a winding support cylinder 31 rotatably journalled on shafts 29 and 30 between side frames 10 and 11. Winding of the wire about the winding support 31 is effected by rotation of cylinder 31 about its longitudinal axis which can be produced such as by use of a crank member 32 appropriately connected to rotatable shaft 30. An electric motor may be used todrive cylinder 31 through the shaft 30, however, the speed of the motor should be accurately controlled as the winding procedure is a delicate one and should be carried out with care and at relatively slow speeds. A crank mechanism has therefore been found to be the most desirable means for rotating the winding support cylinder, to wind the wire thereabout. The wire guide screw 23 is also caused to rotate as the cylinder 31 is rotated by drive chain 28. For this purpose a sprocket wheel 27 is secured to shaft 29 of cylinder 31 and sprocket wheel 26 is secured to shaft 25 of rod 23, the drive chain 28 being supported between these two sprocket wheels. The diameter ratio of sprocket wheel 27 to sprocket wheel 26 is less than one so that the cylinder 31 will make more than one full revolution as rod 23 makes only a single revolution so that the wire will be advanced along cylinder 31 by an amount equal to the pitch of the screw 23 for each turn of the cylinder. This turns ratio will be equal to the ratio of sprocket wheel 27 diameter to the sprocket wheel 26 diameter. A suitable pitch for the screw 23 is obtained by using a 20 pitch screw, that is, 0.05 inch from center to center pitch. With such a pitch, any desired spacing between the wires on cylinder 51 may be obtained down to the diameter of the wire itself.

A set screw 33 is provided on the cylinder 31 for receiving and holding one end of the wire W when a winding operation is to commence. The cylinder 31 is additionally provided with a pair of grooves 34, 35. A pair of strips, preferably made of lucite, 36 and 37 are provided in the grooves of the cylinder. The grooves are spaced approximately 10 apart about the cylinder so there is a space between the lucite strips. After the wire is completely wound about the cylinder 31 an epoxy cement or other suitable adhesive is applied to the lucite strips so that the wound wires W W W are fastened to both of the lucite strips. Each of the wires are then cut in the area between the lucite strips and the strips are removed from the grooves in the cylinder and the wire array removed from the cylinder so that the grid arrangement W shown in FIG. 3 is obtained.

In summary, the operation of the mechanism shown in FIGS. 1 and 2, in order to obtain the loose wire array W, of FIG. 3, is as follows:

The wire W carried on spool 16 is directed over tension maintaining pulley 17 and around wire guide screw 23 onto winding support cylinder 31 being supported as set screw 33. Cylinder 31 is caused to rotate by use of crank handle 32, or other appropriate means, and wire W is hence wound about the cylinder. Wire guide screw 23 is coupled with cylinder 31 by means of sprocket wheels 26, 27 and drive chain 28 so that as cylinder 31 is caused to rotate, rod 23 also rotates and advances the wire along the cylinder. Wire W need not actually come in contact with the guide screw 23, but may rather be guided about a feeder mechanism mounted on the guide screw 23 which advances along guide screw 23 as it is rotated. Tensioning of the wire, as previously pointed out, is effected by friction brake mechanism applied to the spool 16 on collar 19 and floating roller 17. After the wires, which have been wound about the cylinder 31, are securely fastened to the lucite strips, the wire are cut between the lucite strips and the wire array shown in FIG. 3, removed from the cylinder. The length of the wire grid between the lucite strips is predetermined by the diameter of the cylinder and any desired length may be obtained by replacing the cylinder with one of appropriate diameter.

The next step in preparing the wire array for use in the spark chamber apparatus is to stretch the wires between the lucite strips and to shape the array to any desired curved or flat configuration. These steps are carried out in the apparatus shown in FIGS. 4 and S and referred to previously as to the stretching and shaping device.

FIG. 4 and FIG. 5 are side and plan views respectively of the wire stretching and shaping device referred to generally as numeral 40. The device comprises a pair of clamps 41 and 42, each comprising an upper clamping member shown in FIG. 4 as 42a and a lower clamping member shown in FIG. 4 as 42b. The upper surface of the lower clamping member 42b and the lowersurface of the upper clamping member 42a are complementary with each other and define the curved configuration which it is desired that at least one end of the wire array shown in FIG. 3 have. If.it is desired that the curved configuration of the wire array be uniform across its entire width, then the curved surface defind by complimentary upper and lower clamping members of both clamps 41 and 42 will be identical. It is not necessary however, that this curved configuration be the same on both clamps as it might be desirable that the curved surface of the wire array vary in cross-section across its width. A fiat wire array may also be produced by using clamps which have the interface between the upper and lower clamping members (defined by the upper surface 43 of lower clamping member 42b and lower surface 44 of upper clamping member 42a) form a straight line. The upper and lower clamping members of each of the clamps are joined by clamping screws 45. Each of the clamps are slidably mounted and spaced apart on transverse rods 46 and 47, thereby forming a rigid frame construction with the clamps spaced apart in parallel relationship with each other.

In order to stretch and form the wire array to the desired surface configuration, each of the lucite strips are placed in one of the respective clamps between the upper and lower clamping members. Lucite strip 36, with one end of the wires adhered thereto, is placed in clamp 41 between the upper and lower clamping jaws thereof, and lucite strip 37 with the other end of the wires adhered thereto is clamped between upper and lower clamping members 42a and 42b respectively of clamp 42. The clamps 41 and 42 are then forced apart by the action of lead screw 48 operating at one end against clamp 41 and through an internally threaded hole 49 in the lower clamping member 4217. The lead screw 48 is manually operated by handle 50 attached at the other end thereof. In this manner, the wire grid is stretched so that each of the wires is pulled beyond its elastic point and so that the grid is shaped to the desired surface configuration. The grid may now be mounted in a frame construction in the usual manner and the appropriate read-out system connected thereto.

From the foregoing description, it can be seen that an apparatus has been provided for in which a wire grid may be formed and appropriately shaped to any desired curved surface configuration and may be used in wire spark chamber devices in a manner not heretofore fully realized.

While the invention has been described and illustrated with respect to a certain preferred embodiment which gives satisfactory results, it will be understood by those skilled in the art, after understanding the purpose of the invention, that various other changes and modifications may be made without departing from the spirit and scope of the invention, and it is therefore, intended in the apended claims to cover all such changes and modifications.

What is claimed is:

1. An apparatus for fabricating framed wire arrays for use in wire spark chamber devices to detect the position of high energy particles comprising a first unit for winding and spacing said wire array to a desired surface configuration, said first winding and spacing unit comprising: a pair of side frames, a threaded rod fixedly mounted between said side frames for supporting thereon a spool of wire arranged for rotation thereabout, said spool of wire having internal threads for engagement with said threaded rod to that as said spool rotates it will be caused to traverse said rod, a guide screw rotatably journalled between said side frames having its longitudinal axis arranged parallel to the axis of said threaded rod and having a thread pitch equal to the thread pitch of said threaded rod for guiding the wire from said spool, a support cylinder rotatably mounted between said side frames for receiving and winding in spaced relation thereabout the wire from said spool, a pair of longitudinally extending grooves arranged on the outer surface of said cylinder being parallel to each other and to the axis of said cylinder, said grooves being spaced approximately 10 apart, means mounted on said cylinder for attaching thereto one end of said wire, a pair of lucite strips removably carried within said grooves, means connected with said cylinder for causing rotation thereof, a first sprocket wheel fixedly attached to said guide screw, a second sprocket wheel fixedly attached to said cylinder, and a sprocket chain carried between said sprocket wheels so that as said cylinder is rotated with the wire attached thereto said guide screw will be caused to rotate so that as said wire passes thereover it will be advanced therealong and wrapped about said cylinder in proper spaced relation, the'ratio of diameters of said first sprocket wheel to said second sprocket wheel being such that the cylinder will make more than one full revolution for every revolution of said screw, and means for tensioning said wire comprising at least one floating roller between said spool and said cylinder, spring means for biasing said roller so as to tension said wire and a friction brake carried by said spool whereby the wire from said spool may be directed off said roller means to maintain proper tension and a substantially in line relation between said spool and said cylinder, around said guide screw and about the cylinder as said cylinder is rotated, said wire being advanced longitudinally along said guide screw as said guide screw rotates, and said spool being advanced along said threaded rod as said spool rotates, said second stretching and shaping unit comprising: first and second clamping members, each of said clamping members having upper and lower complementary jaws, and means for clamping said jaws together, the interface of said jaws forming a cross-section of the surface configuration to be imparted to said wire array, means extending between said clamping members for maintaining said members in spaced parallel relation, said members being movably mounted on said means for movement toward and away from each other; and a lead screw threaded through said clamping members for causing movement of said members toward and away from each other, whereby said lucite strips carrying the wire array therebetween after removal from said cylinder is clamped in the clamping members to shape the surface of the array and said clamping members are forced apart by said lead screw to thereby stretch the wires of said array and shape the array to the desired surface curvature. 

1. An apparatus for fabricating framed wire arrays for use in wire spark chamber devices to detect the position of high energy particles comprising a first unit for winding and spacing said wire array to a desired surface configuration, said first winding and spacing unit comprising: a pair of side frames, a threaded rod fixedly mounted between said side frames for supporting thereon a spool of wire arranged for rotation thereabout, said spool of wire having internal threads for engagement with said threaded rod to that as said spooL rotates it will be caused to traverse said rod, a guide screw rotatably journalled between said side frames having its longitudinal axis arranged parallel to the axis of said threaded rod and having a thread pitch equal to the thread pitch of said threaded rod for guiding the wire from said spool, a support cylinder rotatably mounted between said side frames for receiving and winding in spaced relation thereabout the wire from said spool, a pair of longitudinally extending grooves arranged on the outer surface of said cylinder being parallel to each other and to the axis of said cylinder, said grooves being spaced approximately 10* apart, means mounted on said cylinder for attaching thereto one end of said wire, a pair of lucite strips removably carried within said grooves, means connected with said cylinder for causing rotation thereof, a first sprocket wheel fixedly attached to said guide screw, a second sprocket wheel fixedly attached to said cylinder, and a sprocket chain carried between said sprocket wheels so that as said cylinder is rotated with the wire attached thereto said guide screw will be caused to rotate so that as said wire passes thereover it will be advanced therealong and wrapped about said cylinder in proper spaced relation, the ratio of diameters of said first sprocket wheel to said second sprocket wheel being such that the cylinder will make more than one full revolution for every revolution of said screw, and means for tensioning said wire comprising at least one floating roller between said spool and said cylinder, spring means for biasing said roller so as to tension said wire and a friction brake carried by said spool whereby the wire from said spool may be directed off said roller means to maintain proper tension and a substantially in line relation between said spool and said cylinder, around said guide screw and about the cylinder as said cylinder is rotated, said wire being advanced longitudinally along said guide screw as said guide screw rotates, and said spool being advanced along said threaded rod as said spool rotates, said second stretching and shaping unit comprising: first and second clamping members, each of said clamping members having upper and lower complementary jaws, and means for clamping said jaws together, the interface of said jaws forming a cross-section of the surface configuration to be imparted to said wire array, means extending between said clamping members for maintaining said members in spaced parallel relation, said members being movably mounted on said means for movement toward and away from each other; and a lead screw threaded through said clamping members for causing movement of said members toward and away from each other, whereby said lucite strips carrying the wire array therebetween after removal from said cylinder is clamped in the clamping members to shape the surface of the array and said clamping members are forced apart by said lead screw to thereby stretch the wires of said array and shape the array to the desired surface curvature. 